CN113969368A - 7-series aluminum alloy ingot for large-size die forgings and control method of hydrogen content of 7-series aluminum alloy ingot - Google Patents
7-series aluminum alloy ingot for large-size die forgings and control method of hydrogen content of 7-series aluminum alloy ingot Download PDFInfo
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Abstract
The invention provides a 7-series aluminum alloy ingot for a large-size die forging, wherein the thickness of the 7-series aluminum alloy ingot is 450-520 mm; the width of the 7-series aluminum alloy cast ingot is 1620-2000 mm; the hydrogen content of the 7-series aluminum alloy ingot is less than or equal to 0.08ml/100g. The invention obtains the 7-series aluminum alloy ingot for the large-size die forging, and the 7-series aluminum alloy ingot for the large-size die forging has stable and lower hydrogen content, so that the micro-porosity size of the ingot can be obviously reduced, the metallurgical quality of the ingot is improved, and a good foundation is laid for developing a new and high-performance aluminum alloy material for subsequent research. The preparation process provided by the invention can stably control the hydrogen content by utilizing self conditions, thereby improving the internal metallurgical quality of the cast ingot. And the process is simple and clear, the operation is easy to understand and operate by operators, the field performability is high, and the method is more suitable for popularization and application of industrial mass production.
Description
Technical Field
The invention belongs to the technical field of preparation of 7-series aluminum alloy ingots, relates to a 7-series aluminum alloy ingot for a large-size die forging and a preparation method thereof, and particularly relates to a 7-series aluminum alloy ingot for a large-size die forging and a hydrogen content control method of the 7-series aluminum alloy ingot for the large-size die forging.
Background
The 7 series aluminum alloy, namely Al-Zn-Mg-Cu series superhard aluminum, is commonly used for parts manufactured by CNC cutting and is suitable for airplane frameworks and high-strength fittings. The 7-series aluminium alloy contains zinc and magnesium, and zinc is the main alloying element in this series, so that the corrosion resistance is quite good, and the addition of a small amount of magnesium alloy makes the material reach a very high strength after heat treatment. The alloy is an ultrahigh strength wrought aluminum alloy which is already applied to the aircraft manufacturing industry in the late 40 th of the 20 th century and is still widely applied to the aircraft industry to date. It features good plasticity after solution treatment, excellent strengthening effect by heat treatment, high strength below 150 deg.C and excellent low-temp. strength. Therefore, the 7-series aluminum alloy is widely applied to the fields of aerospace, die machining, mechanical equipment, tool fixtures and the like, and is particularly used for manufacturing structures of aircrafts such as aerospace and other high-stress structural bodies with high requirements on strength and strong corrosion resistance.
However, the 7-series aluminum alloy has high alloying degree and a wider solidification interval, so that the alloy ingot is easy to generate internal metallurgical defects such as micro-porosity and regional component segregation, the mechanical property of the ingot is reduced by the micro-porosity, and the fatigue life and the tensile strength of the large-size casting are greatly influenced.
However, for the existing 7-series aluminum alloy ingot production, particularly for the ingot of a large-scale die forging for aerospace, due to strict requirements and large size, the existing conventional production process is easy to fluctuate in the aspect of casting technology control of the 7-series large-scale ingot, and is difficult to meet the index requirements of the ingot for the large-scale die forging, thereby causing poor quality of the ingot.
Therefore, how to reduce the micro-porosity size of the cast ingot, improve the metallurgical quality of the large-size 7-series aluminum alloy cast ingot, lay a good foundation for the subsequent research and development of a new and high-performance aluminum alloy material, improve the market share of the 7-series alloy, contribute a strength for the localization path, and become one of the problems to be solved by domestic production enterprises and front-line researchers.
Disclosure of Invention
In view of this, the technical problem to be solved by the invention is to provide a 7-series aluminum alloy ingot and a preparation method thereof, in particular to a 7-series aluminum alloy ingot for large-size die forgings. The 7-series aluminum alloy ingot provided by the invention has stable and lower hydrogen content, can obviously reduce the micro-porosity size of the ingot, improves the metallurgical quality of the ingot, has simple and clear process, strong controllability and high field performability, and is suitable for popularization and application of industrial mass production.
The invention provides a 7-series aluminum alloy ingot for a large-size die forging, wherein the thickness of the 7-series aluminum alloy ingot is 450-520 mm;
the width of the 7-series aluminum alloy cast ingot is 1620-2000 mm;
the hydrogen content of the 7-series aluminum alloy ingot is less than or equal to 0.08ml/100g.
Preferably, the hydrogen content of the 7-series aluminum alloy ingot is 0.05-0.08 ml/100 g.Al;
the thickness of the 7-series aluminum alloy ingot is 520 mm;
the width of the 7-series aluminum alloy cast ingot is 1600 mm.
Preferably, the maximum micro-loose size of the 7 series aluminum alloy cast ingot is less than or equal to 100 x 40 μm;
and controlling the micro-porosity size of the 7-series aluminum alloy cast ingot by controlling the hydrogen content in the 7-series aluminum alloy cast ingot.
Preferably, the 7-series aluminum alloy ingot is a square ingot;
the large-size die forging comprises a large-size die forging for aerospace.
Preferably, the 7-series aluminum alloy ingot comprises the following components in percentage by weight:
Cu：2.05％～2.30％；
Mg：2.00％～2.25％；
Zn：6.10％～6.50％；
Zr：0.09％～0.11％；
Si：≤0.04％；
Fe：≤0.06％；
Mn：≤0.02％；
Ti：≤0.05％；
Cr：≤0.02％；
Na：≤5ppm；
the balance being aluminum.
The invention also provides a preparation method of the 7-series aluminum alloy ingot for the large-size die forging, which comprises the following steps:
1) after batching, charging and smelting an aluminum alloy raw material to obtain a raw material melt;
adding an additive Al-Be intermediate alloy into a converter launder;
2) refining the raw material melt obtained in the step in a furnace, degassing on line, and casting to obtain a 7-series aluminum alloy ingot;
the smelting temperature is 740-760 ℃.
Preferably, the aluminum alloy raw material comprises one or more of a Zn ingot, a Cu plate, an Mg ingot, an Al-Zr intermediate alloy and a remelted high-precision aluminum ingot.
Preferably, the gas flow rate of the refining in the furnace is 10-20 ml/min;
the refining temperature of the in-furnace refining is 730-745 ℃;
and the refining time of the furnace refining is 30-45 min.
Preferably, the speed of the rotor for online degassing is 230-270 rpm;
the gas flow rate of the online degassing is 3.5-5Nm3/h。
Preferably, the casting temperature is 725-740 ℃;
the casting speed is 43-47 mm/min;
the flow rate of the cast cooling water is 25-40 m3H/root.
The invention provides a 7-series aluminum alloy ingot for a large-size die forging, wherein the thickness of the 7-series aluminum alloy ingot is 450-520 mm; the width of the 7-series aluminum alloy cast ingot is 1620-2000 mm; the hydrogen content of the 7-series aluminum alloy ingot is less than or equal to 0.08ml/100g. Compared with the prior art, the invention aims at the self characteristics of the existing 7-series aluminum alloy, the alloy cast ingot is easy to generate the conditions of internal metallurgical defects such as micro-porosity, regional component segregation and the like, and the existing conventional production process is easy to fluctuate in the aspect of casting technology control, is difficult to meet the index requirements of the cast ingot for large-size die forgings and further causes the problem of poor quality of the cast ingot. According to the invention, the research shows that the hydrogen content of the 7-series alloy large-size cast ingot needs to be controlled firstly to control the micro-porosity size of the ingot. In the aspect of controlling the hydrogen content of the 7-series alloy large-specification flat ingot, the hydrogen content of a 520 x 1600 mm-specification ingot produced by the conventional large die forging is controlled within the range of 0.06-0.12 ml/100.Al, the fluctuation is large, the hydrogen content of part of furnace is over 0.10ml/100g. Al, the requirement of the hydrogen content index of the ingot for the large-specification die forging is difficult to meet, the technical requirement of the large die forging for aerospace on the hydrogen content control of the ingot is quite high, the liquid hydrogen content must be less than or equal to 0.08ml/100ml/100g. Al, and the solid hydrogen content is less than or equal to 0.10 mu g/g. However, the requirement of the existing aluminum alloy casting technology of the 7-series large-specification cast ingot is difficult to guarantee, so the invention starts with the research of the purification process and optimizes the existing purification process, thereby controlling the hydrogen content of the 7-series aluminum alloy cast ingot, particularly the 520 x 1600 mm-specification cast ingot for the large-specification die forging, and further improving the quality and the stability of the cast ingot.
The invention obtains the 7-series aluminum alloy ingot for the large-size die forging, and the 7-series aluminum alloy ingot for the large-size die forging has stable and lower hydrogen content, so that the micro-porosity size of the ingot can be obviously reduced, the metallurgical quality of the ingot is improved, and a good foundation is laid for developing a new and high-performance aluminum alloy material for subsequent research.
The preparation method of the 7-series aluminum alloy ingot for the large-size die forging, which is provided by the invention, is a hydrogen content control method of the 7-series aluminum alloy ingot for the large-size die forging, and is very important as a first procedure for reducing the hydrogen content of a melt by virtue of the smelting temperature and the adding time of the Al-Be intermediate alloy; and correspondingly adjusting and optimizing the refining process in the furnace, controlling process parameters such as gas flow, refining temperature, refining time and the like, and combining the parameter coordination of on-line degassing such as gas flow, rotating speed and the like, thereby preparing the 7-series aluminum alloy ingot for the large-specification die forging with excellent quality. The preparation process provided by the invention can stably control the hydrogen content by utilizing self conditions without increasing investment cost, further improve the internal metallurgical quality of the cast ingot, and improve the market share of the 7-series alloy in the aerospace field, and has the advantages of simple and clear process operation, easy operation by operators, strong controllability, high field performability, and is more suitable for popularization and application of industrial scale production.
The industrial production result shows that the content of liquid hydrogen of the 7-series aluminum alloy ingot for the large-specification die forging prepared by the invention is less than or equal to 0.08ml/100g.Al, the content of solid hydrogen is less than or equal to 0.10 mu g/g, and the micro-porosity size is less than or equal to 100 x 40 mu m.
Drawings
FIG. 1 is a metallographic image of the microstructure of a 7-series aluminum alloy ingot prepared according to an example of the present invention;
FIG. 2 is a metallographic image of a microstructure of an ingot gate portion of a 7-series aluminum alloy ingot produced by an example of the present invention;
FIG. 3 is a metallographic image of the microstructure of the ingot bottom of a 7-series aluminum alloy ingot prepared according to an example of the present invention;
FIG. 4 is a gold phase diagram of the microstructure of a 7-series aluminum alloy ingot produced by a conventional process before modification.
Detailed Description
For a further understanding of the invention, reference will now be made to the preferred embodiments of the invention by way of example, and it is to be understood that the description is intended to further illustrate features and advantages of the invention, and not to limit the scope of the claims.
All of the starting materials of the present invention, without particular limitation as to their source, may be purchased commercially or prepared according to conventional methods well known to those skilled in the art.
All the raw materials of the invention are not particularly limited in purity, and the invention preferably adopts the purity requirements which are conventional in the field of industrial pure or 7-series aluminum alloy preparation.
All the raw materials, the marks and the acronyms thereof belong to the conventional marks and acronyms in the field, each mark and acronym is clear and definite in the field of related application, and the raw materials can be purchased from the market or prepared by a conventional method by the technical staff in the field according to the marks, the acronyms and the corresponding application.
The process used in the invention belongs to the field of general abbreviation, the specific steps and general parameters of each abbreviation are clear and definite in the related field, and the technicians in the field can realize the process by the general method according to the abbreviation.
The invention provides a 7-series aluminum alloy ingot for a large-size die forging, wherein the thickness of the 7-series aluminum alloy ingot is 450-520 mm;
the width of the 7-series aluminum alloy cast ingot is 1620-2000 mm;
the hydrogen content of the 7-series aluminum alloy ingot is less than or equal to 0.08ml/100g.
In the invention, the hydrogen content of the 7-series aluminum alloy ingot is less than or equal to 0.08ml/100g. Specifically, the hydrogen content of the 7-series aluminum alloy ingot is preferably 0.05-0.08 ml/100g.Al, more preferably 0.055-0.075 ml/100g.Al, and more preferably 0.06-0.07 ml/100 g.Al.
The invention controls the micro-porosity size of the 7 series aluminum alloy cast ingot by controlling the hydrogen content in the 7 series aluminum alloy cast ingot. In particular, in the present invention, the maximum micro-porosity of the 7-series aluminum alloy ingot is preferably 100 × 40 μm or less, more preferably 80 × 30 μm or less, still more preferably 60 × 30 μm or less, and still more preferably 50 × 20 μm or less. In the present invention, the maximum microscopic bulk size of the gate portion of the 7-series aluminum alloy ingot is preferably not more than 80 × 40 μm, more preferably not more than 70 × 30 μm, and still more preferably not more than 60 × 20 μm. The maximum microscopic bulk size of the bottom of the 7-series aluminum alloy ingot is preferably 60 × 40 μm or less, more preferably 50 × 30 μm or less, and still more preferably 40 × 20 μm or less.
In the invention, the thickness of the 7-series aluminum alloy ingot is 450 to 520mm, preferably 460 to 510mm, more preferably 470 to 500mm, more preferably 480 to 500mm,
in the present invention, the width of the 7-series aluminum alloy ingot is 1620 to 2000mm, preferably 1670 to 1950mm, more preferably 1720 to 1900mm, and more preferably 1770 to 1850 mm.
In the present invention, the 7-series aluminum alloy ingot is preferably a square ingot.
In the present invention, the thickness of the 7-series aluminum alloy ingot is preferably 520 mm.
In the present invention, the width of the 7-series aluminum alloy ingot is preferably 1600 mm.
In the present invention, the 7-series aluminum alloy ingot preferably includes, by composition:
Cu：2.05％～2.30％；
Mg：2.00％～2.25％；
Zn：6.10％～6.50％；
Zr：0.09％～0.11％；
Si：≤0.04％；
Fe：≤0.06％；
Mn：≤0.02％；
Ti：≤0.05％；
Cr：≤0.02％；
Na：≤5ppm；
the balance being aluminum.
In the composition and content of the 7-series aluminum alloy, the mass content of Cu is preferably 2.05-2.30%, more preferably 2.1-2.25%, and more preferably 2.15-2.2%. The mass content of Mg is preferably 2.00% to 2.25%, more preferably 2.05% to 2.2%, and still more preferably 2.1% to 2.15%. The mass content of Zn is preferably 6.10% to 6.50%, more preferably 6.15% to 6.45%, more preferably 6.2% to 6.4%, more preferably 6.25% to 6.35%. The mass content of Zr is preferably 0.09% to 0.11%, more preferably 0.094% to 0.106%, and still more preferably 0.098% to 0.102%.
In the present invention, the mass content of Si is preferably not more than 0.04%, and may be 0.001% to 0.04%, and may be 0.002% to 0.03%. The mass content of the Fe is preferably less than or equal to 0.06%, can be 0.001-0.05%, and can be 0.002-0.04%. The mass content of Mn is preferably less than or equal to 0.02%, may be 0.001-0.02%, and may be 0.005-0.01%. The mass content of Ti is preferably less than or equal to 0.05%, can be 0.001-0.05%, can be 0.005-0.04%, and can be 0.01-0.03%. The mass content of Cr is preferably less than or equal to 0.02%, and may be 0.001-0.02%, and may be 0.005-0.01%. The Na content is preferably not more than 5ppm by mass, and may be 0.1ppm to 5ppm by mass, may be 0.5ppm to 4ppm by mass, and may be 1ppm to 3ppm by mass.
In the invention, the large-size die forging preferably comprises a large-size die forging for aerospace.
The invention provides a preparation method of a 7-series aluminum alloy ingot for a large-size die forging, which comprises the following steps:
1) after batching, charging and smelting an aluminum alloy raw material to obtain a raw material melt;
adding an additive Al-Be intermediate alloy into a converter launder;
2) refining the raw material melt obtained in the step in a furnace, degassing on line, and casting to obtain a 7-series aluminum alloy ingot;
the smelting temperature is 740-760 ℃.
Firstly, aluminum alloy raw materials are proportioned and then are put into a furnace to be smelted to obtain raw material melt; wherein, the additive Al-Be intermediate alloy is added into a converter launder.
In the present invention, the aluminum alloy raw material preferably includes one or more of a Zn ingot, a Cu plate, an Mg ingot, an Al-Zr intermediate alloy, and a remelted high-precision aluminum ingot, and more preferably a plurality of Zn ingot, a Cu plate, an Mg ingot, an Al-Zr intermediate alloy, and a remelted high-precision aluminum ingot.
The invention is a complete and refined integral preparation process, the hydrogen content of the 7-series aluminum alloy cast ingot for the large-size die forging is better reduced and kept stable, the metallurgical quality of the cast ingot is improved, the cleanliness of the raw and auxiliary materials is also controlled, and the pollution and oil stain prevention of the raw and auxiliary materials for producing the 7-series alloy are ensured.
The invention particularly controls the smelting temperature to Be 740-760 ℃, and adds the Al-Be intermediate alloy into the converter launder, thereby improving the existing smelting temperature of 700-730 ℃ and the process of adding the Al-Be intermediate alloy along with the converter. The invention considers that the higher the melt temperature is, the larger the hydrogen absorption amount of the melt is; the lower the temperature of the melt is, the floating of slag in the melt is not facilitated, and the hydrogen content can be caused by the symbiosis of slag and gas, so that the hydrogen content of the melt can be reduced by proper smelting temperature. The addition of the Mg element can reduce the density of the oxide film on the surface of the melt, and the addition of the Be element can effectively improve the density of the oxide film on the surface of the melt, reduce hydrogen absorption of the melt and simultaneously reduce the burning loss of Mg, so the invention reduces the melting temperature and changes the adding time of the Al-Be intermediate alloy.
Refining the raw material melt obtained in the step in a furnace and degassing on line, and then casting to obtain a 7-series aluminum alloy ingot;
the smelting temperature is preferably 740-760 ℃, more preferably 744-756 ℃, and more preferably 748-752 ℃.
In the invention, the gas flow rate of the refining in the furnace is preferably 10-20 ml/min, more preferably 12-18 ml/min, and more preferably 14-16 ml/min.
In the present invention, the refining temperature in the furnace refining is preferably 730 to 745 ℃, more preferably 733 to 742 ℃, and more preferably 736 to 739 ℃.
In the invention, the refining time of the furnace refining is preferably 30-45 min, more preferably 33-42 min, and more preferably 36-39 min.
The research of the invention considers that the main factors influencing the dehydrogenation effect in the refining process in the furnace are the gas flow, the refining temperature and the refining time. If the gas flow is too small, the number of bubbles is small, the hydrogen outlet effect is poor, the bubbles can generate the bubble diameter spreading and bubble combination phenomenon along with the increase of the gas flow, and the degassing efficiency can also be reduced. The high-temperature melt is easy to absorb hydrogen at the refining temperature, and the gas in the low-temperature melt is not easy to overflow. When the refining time is too short, the hydrogen removal effect cannot be achieved, and when the refining time is too long, the hydrogen removal effect is saturated, the melt can absorb hydrogen due to reverse falling. Therefore, the hydrogen content in the melt can be effectively reduced by controlling proper gas flow, refining temperature and refining time.
Therefore, the invention particularly controls the gas flow to be 10-20 ml/min, the melt refining temperature to be 730-745 ℃, and the refining time to be 30-45 min.
In the invention, the rotor speed of the online degassing is preferably 230-270rpm, more preferably 235-265 rpm, more preferably 240-260 rpm, and more preferably 245-255 rpm.
In the invention, the gas flow rate of the online degassing is preferably 3.5-5Nm3More preferably 3.8 to 4.7Nm3More preferably 4.1 to 4.4Nm3/h。
In the invention, the casting temperature is preferably 725-740 ℃, more preferably 728-737 ℃, and more preferably 731-734 ℃.
In the invention, the casting speed is preferably 43-47 mm/min, more preferably 43.5-46.5 mm/min, more preferably 44-46 mm/min, and more preferably 44.5-45.5 mm/min.
In the invention, the flow rate of the cooling water for casting is preferably 25-40 m3A/h/root, more preferably 28 to 37m3A/h/root, more preferably 31 to 34m3H/root.
The research of the invention considers that the main influencing factors of the hydrogen removal efficiency in the on-line degassing process are the gas flow and the rotor rotating speed, and the mass transfer coefficient is improved along with the improvement of the refining gas flow and the rotating speed. That is, as the rotor rotation speed and the refining gas flow rate increase, the melt gas content decreases, but after the rotation speed and the refining gas flow rate increase excessively, the high rotation speed and the large refining gas flow rate are easy to cause vortex and turbulent flow at the liquid surface to cause melt lapThe risk of slag aspiration increases. Therefore, the present invention particularly controls the rotor speed to 230 to 270rpm and the gas flow rate to 3.5 to 5Nm3/h。
Finally, the invention combines specific casting parameters to carry out casting, and obtains the 7-series aluminum alloy cast ingot for the large-specification die forging.
The invention provides a preparation method of a 7-series aluminum alloy cast ingot for a large-specification die forging, which is characterized in that the following 5 points are mainly controlled for producing the 7-series alloy large-specification die forging: 1. the cleanliness of the raw and auxiliary materials; 2. smelting temperature and adding time of Al-Be intermediate alloy; 3. refining process in furnace; 4. and (3) degassing parameters on line, so that the ingot for the 7-series alloy large-specification die forging with stable and low hydrogen content, obviously reduced micro-porosity size of the ingot and improved metallurgical quality of the ingot is obtained.
The steps of the invention provide a 7-series aluminum alloy ingot for large-specification die forgings and a hydrogen content control method of the 7-series aluminum alloy ingot for large-specification die forgings. The cast ingot for the 7-series aluminum alloy large-size die forging has stable and lower hydrogen content, so that the micro-porosity size of the cast ingot can be obviously reduced, the metallurgical quality of the cast ingot is improved, and a good foundation is laid for developing a new and high-performance aluminum alloy material for subsequent research.
The preparation method of the 7-series aluminum alloy ingot for the large-size die forging, which is provided by the invention, is a hydrogen content control method of the 7-series aluminum alloy ingot for the large-size die forging, and is very important as a first procedure for reducing the hydrogen content of a melt by virtue of the smelting temperature and the adding time of the Al-Be intermediate alloy; and correspondingly adjusting and optimizing the refining process in the furnace, controlling process parameters such as gas flow, refining temperature, refining time and the like, and combining the parameter coordination of on-line degassing such as gas flow, rotating speed and the like, thereby preparing the 7-series aluminum alloy ingot for the large-specification die forging with excellent quality. The preparation process provided by the invention can stably control the hydrogen content by utilizing self conditions without increasing investment cost, further improve the internal metallurgical quality of the cast ingot, and improve the market share of the 7-series alloy in the aerospace field, and has the advantages of simple and clear process operation, easy operation by operators, strong controllability, high field performability, and is more suitable for popularization and application of industrial scale production.
The industrial production result shows that the content of liquid hydrogen of the 7-series aluminum alloy ingot for the large-specification die forging prepared by the invention is less than or equal to 0.08ml/100g.Al, the content of solid hydrogen is less than or equal to 0.10 mu g/g, and the micro-porosity size is less than or equal to 100 x 40 mu m.
For further illustration of the present invention, the following will describe in detail a 7-series aluminum alloy ingot for large-size die forging and a method for making the same with reference to the following examples, but it should be understood that these examples are implemented on the premise of the technical solution of the present invention, and the detailed embodiments and specific operation procedures are given, only for further illustration of the features and advantages of the present invention, but not for limitation of the claims of the present invention, and the scope of protection of the present invention is not limited to the following examples.
Examples
Chemical composition control, see table 1. Table 1 shows the content of the 7-series aluminum alloy ingots for large-sized die forgings prepared in the examples of the present invention.
TABLE 1
(1) The use proportion of the returned materials is as follows: less than or equal to 60 percent, and using an Al-Ti rod for burdening.
(2) Temperature and timing of Al-Be addition: 740 ℃ and 760 ℃, adding the mixture into a converter launder
(3) Standing and purifying in a furnace: the refining medium is argon, the pressure of the argon is 0.25-0.4MPa, the flow of the argon is 10-20L/min/block, and meanwhile, the manual refining is assisted for 2 times and 35 minutes. The refining temperature is 725 and 745 ℃.
(4) An online purification process: the gas pressure is 0.1-0.3Mpa, and the rotor speed is 230-. Ar gas flow rate of 3.5-5Nm3H, Cl gas flow rate of 0.03-0.045Nm3/h
(5) A filtering device: 60+600ppi parallel
(6) Casting process parameters are as follows: casting speed is 45-50mm/min, and water flow is 70-90m3H, casting temperatureThe temperature is 725 ℃ and 745 ℃, the wiper position is 380 mm +/-30 mm, and the adding amount of the online grain refiner is 1.6-2.0 kg/t.
The large-size die forging prepared by the embodiment of the invention is characterized by using a 7-series aluminum alloy ingot.
Referring to fig. 1, fig. 1 is a gold phase diagram of the microstructure of a 7-series aluminum alloy ingot prepared according to an example of the present invention.
As can be seen from fig. 1, the maximum microscopic porosity size of the microstructure of the aluminum alloy ingot obtained by the present invention was 40 × 10 μm, based on the measurement by the standard of the instrument.
Referring to fig. 2, fig. 2 is a gold phase diagram showing the microstructure of the ingot gate portion of a 7-series aluminum alloy ingot prepared according to an example of the present invention.
As can be seen from fig. 2, the maximum micro-porosity size in the microstructure of the ingot gate portion of the aluminum alloy ingot obtained by the present invention was 60 × 20 μm, based on the measurement by the standard instrument.
Referring to fig. 3, fig. 3 is a gold phase diagram of the microstructure of the ingot bottom of a 7-series aluminum alloy ingot prepared by an example of the present invention.
As can be seen from fig. 3, the maximum microscopic porosity size of the microstructure at the bottom of the ingot of the aluminum alloy ingot obtained by the present invention was 40 × 20 μm, based on the measurement by the standard of the instrument.
Referring to fig. 4, fig. 4 is a gold phase diagram of the microstructure of a 7-series aluminum alloy ingot produced by a conventional process before modification.
As can be seen from comparison of FIGS. 1 to 3 with FIG. 4, the micro-porosity size of the 7-series aluminum alloy ingot prepared by the method is significantly reduced.
The performance of the 7-series aluminum alloy cast ingot for the large-specification die forging prepared by the embodiment of the invention is detected.
And (3) detection: the liquid hydrogen content is less than or equal to 0.08ml/100gAl, the solid hydrogen content is less than or equal to 0.10ug/g, the micro-porosity is less than or equal to 100 x 40um, and the die forging piece is qualified in flaw detection.
According to ASTM E34 aluminum alloy analysis method, 90 aluminum alloy ingots were prepared and tested for high-power micro-porosity with a micro-porosity size of 100 x 40 um.
Referring to table 2, table 2 shows the micro-porosity size of 90-heat series 7-aluminum alloy ingots prepared according to examples of the present invention.
TABLE 2
According to ASTM E2792 Standard test method for inert gas melting determination of hydrogen in aluminum or aluminum alloy, 90 aluminum alloy ingots are prepared and obtained for multiple times according to the method of the embodiment, liquid and solid hydrogen content detection is carried out, all detection results are qualified, and the qualification rate is 100%.
Referring to table 3, table 3 shows the liquid and solid hydrogen content results for 90 heats prepared according to the examples of the present invention.
TABLE 3
The above detailed description of the hydrogen content control method for the 7-series aluminum alloy ingot for the large-size die forging and the 7-series aluminum alloy ingot for the large-size die forging provided by the invention have been provided, and the specific examples are applied herein to explain the principle and the embodiments of the invention, and the above description of the embodiments is only used to help understand the method and the core idea of the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any device or system, and implementing any method in combination. It should be noted that, for those skilled in the art, it is possible to make various improvements and modifications to the present invention without departing from the principle of the present invention, and those improvements and modifications also fall within the scope of the claims of the present invention. The scope of the invention is defined by the claims and may include other embodiments that occur to those skilled in the art. Such other embodiments are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.
Claims (10)
1. A7-series aluminum alloy ingot for a large-size die forging is characterized in that the thickness of the 7-series aluminum alloy ingot is 450-520 mm;
the width of the 7-series aluminum alloy cast ingot is 1620-2000 mm;
the hydrogen content of the 7-series aluminum alloy ingot is less than or equal to 0.08ml/100g.
2. The 7-series aluminum alloy ingot according to claim 1, wherein the hydrogen content of the 7-series aluminum alloy ingot is 0.05 to 0.08ml/100 g.Al;
the thickness of the 7-series aluminum alloy ingot is 520 mm;
the width of the 7-series aluminum alloy cast ingot is 1600 mm.
3. The 7-series aluminum alloy ingot according to claim 1, wherein the maximum micro-porosity size of the 7-series aluminum alloy ingot is 100 x 40 μm or less;
and controlling the micro-porosity size of the 7-series aluminum alloy cast ingot by controlling the hydrogen content in the 7-series aluminum alloy cast ingot.
4. The 7-series aluminum alloy ingot according to claim 1, wherein the 7-series aluminum alloy ingot is a square ingot;
the large-size die forging comprises a large-size die forging for aerospace.
5. The 7-series aluminum alloy ingot according to claim 1, wherein the 7-series aluminum alloy ingot comprises, by composition:
Cu：2.05％～2.30％；
Mg：2.00％～2.25％；
Zn：6.10％～6.50％；
Zr：0.09％～0.11％；
Si：≤0.04％；
Fe：≤0.06％；
Mn：≤0.02％；
Ti：≤0.05％；
Cr：≤0.02％；
Na：≤5ppm；
the balance being aluminum.
6. A preparation method of a 7-series aluminum alloy ingot for a large-size die forging is characterized by comprising the following steps:
1) after batching, charging and smelting an aluminum alloy raw material to obtain a raw material melt;
adding an additive Al-Be intermediate alloy into a converter launder;
2) refining the raw material melt obtained in the step in a furnace, degassing on line, and casting to obtain a 7-series aluminum alloy ingot;
the smelting temperature is 740-760 ℃.
7. The production method according to claim 6, wherein the aluminum alloy raw material includes one or more of a Zn ingot, a Cu plate, an Mg ingot, an Al-Zr intermediate alloy, and a remelted high-precision aluminum ingot.
8. The method according to claim 6, wherein the flow rate of the gas for the furnace refining is 10 to 20 ml/min;
the refining temperature of the in-furnace refining is 730-745 ℃;
and the refining time of the furnace refining is 30-45 min.
9. The preparation method according to claim 6, wherein the rotor speed of the on-line degassing is 230-270 rpm;
the gas flow rate of the online degassing is 3.5-5Nm3/h。
10. The method according to claim 6, wherein the casting temperature is 725 to 740 ℃;
the casting speed is 43-47 mm/min;
the flow rate of the cast cooling water is 25-40 m3H/root.
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